STRUCTURAL STUDIES OF A SULFATED L-GALACTAN FROM STYELA-PLICATA (TUNICATE) - ANALYSIS OF THE SMITH-DEGRADED POLYSACCHARIDE

The tunic of the ascidian Styela plicata is rich in a high molecular weight sulfated l-galactan called the F-1 fraction. This polysaccharide is of complex structure and is highly branched. In this study we undertook detailed structural analysis of the F-1 fraction that was submitted to the Smith degradation procedure which, for this polysaccharide, results mainly in the elimination of the branches. By methylation, and on-e and two-dimensional n.m.r. analysis of the Smith-degraded and desulfated Smith-degraded F-1 fraction, we determined the main structure of this polymer. It is composed of a core of α-l-galactopyranose units, sulfated at C-3 and glycosidically linked through position 1 »4. The nonsulfated, nonreducing end units are branched at C-2 of the sulfated l-galactoses. © 1990.